package com.atguigu.day09;

import com.atguigu.bean.WaterSensor;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.table.functions.ScalarFunction;

import static org.apache.flink.table.api.Expressions.$;
import static org.apache.flink.table.api.Expressions.call;

public class Flink01_UDF_ScalarFun {
    public static void main(String[] args) {
        //1获取流的执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        env.setParallelism(1);

        //2.从端口读取数据
        SingleOutputStreamOperator<WaterSensor> streamOperator = env.socketTextStream("localhost", 9999)
                .map(new MapFunction<String, WaterSensor>() {
                    @Override
                    public WaterSensor map(String value) throws Exception {
                        String[] split = value.split(",");
                        return new WaterSensor(split[0], Long.parseLong(split[1]), Integer.parseInt(split[2]));
                    }
                });


        //3.获取表的执行环境
        StreamTableEnvironment tableEnv = StreamTableEnvironment.create(env);

        //4.将流转为表
        Table table = tableEnv.fromDataStream(streamOperator);

//        table
//                .select($("id"),call(MyUDF.class,$("id")))
//                .execute()
//                .print();

        //TODO 注册一个自定义函数
        tableEnv.createTemporarySystemFunction("idLen", MyUDF.class);

/*        table
                .select($("id"),call("idLen",$("id")))
                .execute()
                .print();*/

        tableEnv.executeSql("select id,idLen(id) from "+table).print();
    }

    //自定义一个标量函数（一进一出） 根据id获取到id的字符串长度
    public static class MyUDF extends ScalarFunction {
        public Integer eval(String value) {
            return value.length();
        }
    }
}
